1. Field
This invention relates to automated material handling systems. It is particularly directed to mechanized systems for receiving, storing, and delivering goods quickly and in a desired selected order.
2. State of the Art
There are widespread needs for material handling systems capable of receiving, storing and delivering goods in a selected order. Many such systems, often referred to as "order picking systems," have been developed. Such systems constitute means for reducing manual handling of goods; improving the accuracy of goods handling; increasing the volume of goods that can be handled; and reducing the number of injuries to workers.
Order picking systems are applied to a wide variety of circumstances and environments. In general, they may be regarded as involving the retrieval ("picking") of designated goods from various designated storage locations ("addresses") from which they are delivered to a remote accumulation center. Upon accumulation, the goods are sorted into individual lots or orders. A typical objective of an order picking system is to retrieve individual case lots of designated goods from diverse locations within a warehouse and to assemble (palletize) the retrieved cases into ranks and files in a plurality of layers stacked on a pallet. While many of the operations required for such systems have been mechanized, the delivery and organization of cases of different goods or styles of goods to the final assembly or palletizing stage of the delivered cases has generally involved considerable manual labor.
Material handling systems developed in the past have combined known devices, such as conveyer belts, empty pallet feeders, depalletizers, unscramblers, wrappers and similar apparatus. These systems have typically adopted a horizontal flow, rack/conveyor approach that has proven to be costly, complex, unreliable and difficult to maintain. These known systems are also generally incapable of meeting changing needs. Once installed, they have been unduly limited as to the amount of material that can be processed and the speed with which product can be delivered from storage to a pick-up location.
U.S. Pat. No. 4,621,745 to Grace discloses a mechanized carton picker configured as a vertically accumulating and dispensing apparatus for containers. Cartons, cases or other suitable containers are loaded by a feed conveyor discharging onto a supply conveyor that feeds the top of a tower. The containers are dispensed seriatim, as needed, from the bottom of the tower, e.g., onto a moving discharge conveyor belt. The vertical tower thus provides a vertical queue or stack of containers of a product in storage. The individual containers progress via tilting shelves from the top to the bottom of the queue as containers lower in the queue are dispensed. Additional containers are loaded at the top of the tower as required to maintain inventory.
The use of vertical storage systems has been well known as a means of achieving maximum use of storage space. For years, it has been common to use operator controlled fork lifts and cherry pickers to travel between banks of high rise storage shelves. An individual operating such equipment can place items on the storage shelves for storage and subsequently remove the items from the shelves for delivery to a collection location. While providing for efficient use of available storage space, the use of high rise shelving and manual placement of goods for storage and removal of the goods on a selected basis for delivery is slow and labor intensive. In addition, further labor is often required to consolidate the selected goods for efficient delivery to a pick-up location.
It is not uncommon for workers to make mistakes while placing, retrieving or consolidating the goods, or for workers to be injured in the performance of their jobs.
More recently, various proposals have been made for storage and distribution systems utilizing computers to control flow of goods both into storage and out for delivery, while maintaining accurate data on the availability of goods and their locations.
It has also become widely accepted, particularly in the grocery business, as well as in other businesses such as, for example, those dealing with soft goods, automotive supplies, parts supplies and many other types of products, to deliver the goods to a pick-up location on pallets. The delivery location may be a truck, box car or other transport system or may merely be a storage location where the goods await further handling and transport.
The pallets for a particular industry are generally essentially standardized in size and loading. In the grocery industry, for example, the pallets are most often rectangular and are typically forty inches wide by forty-eight inches long by five inches thick. Standard pallets of this size will conveniently and efficiently fit into and fill trucks, box cars, sea containers, etc. The pallets are generally loaded with cases containing the goods and with the cases arranged in layers. Each layer is arranged to be able to support another layer or layers, and a typical such pallet may support as many as forty to eighty cases. The manner of loading each pallet depends on the type of cases delivered and whether different case types need to be placed on a pallet in correspondingly different patterns.
When it is determined that goods are to be delivered to a pick-up or staging location, it is possible that the order placed for such goods may be for full pallets of one type of goods or full pallets of a number of different types of goods. The order may require pallets having specific layers dedicated to cases of respective types of goods or the order may require pallets having layers of cases of mixed types of goods. The orders for goods may include some full pallets of goods of one type or another, some pallets with different goods making up individual layers and for other pallets with mixed cases of goods within layers on the pallets.
In the past, computers have been used to determine order requirements and even to control delivery of goods to a location for storage and release of the goods for transport to a pick-up location. There has not heretofore been available any system capable of monitoring and controlling storage goods, storage replenishment as the goods are delivered from storage and the versatile delivery of the goods by full pallet. By "versatile delivery" is meant by pallet loads which are selectively loaded either by the same type goods, individual layers of different specified goods or different type goods in cases that are mixed within layers.
The development in recent years of mechanized and computer controlled robots having capabilities for selecting, picking up, transporting, and releasing selected goods of various types and in different patterns greatly increases the possibilities for mechanical handling of goods.
C&D Robotics of Beaumont, Tex. currently manufactures and markets robot units that are used in industry. Typical of the robot units currently marketed are open gantry units having a cantilevered axis and closed gantry units having a totally enclosed motion. C&D Robotics currently produces standard robot units having total load capacities, i.e. product carried, plus end effector used, of 120 to 350 pounds. Non-standard, structurally modified robot units are available to handle heavier loads, even exceeding 1,000 pounds.
The standard end effectors available for use with the C&D robotic units fall into a few general categories, for example: "fork and clamps," where bottom forks support the goods, while a top clamp steadies the goods for handling; "vacuum," where suction is produced either by venturi action created using compressed air or by an integral blower with cups or platens, as required; "variable pitch vacuum," using vacuum cups that adjust under program control to handle a wide range of products; "top clamp," wherein parallel clamps are used on two or four sides of the product; and "hybrid," which comprises combinations or extensions of the other types.
U.S. Pat. No. 4,621,745 discloses a mechanized carton picker wherein vertical storage and dispensing apparatus is provided for the handling of containers of goods. Goods are loaded at the top of a tower and are selectively discharged from the bottom. The tower has a frame that defines first and second tower sections each supporting a number of vertically spaced shelf trays to support the containers placed on the trays when the tower is loaded. Each tray is mounted for cantilevered pivotal movement about a horizontal axis and is operated so that when a container is dispensed from a bottom shelf tray of one tower section, each higher tray of the tower sections, beginning at the bottom and progressing upward, one at a time, pivots to transfer its container to the next lower, upwardly tilted tray of the other tower section. The process is repeated until each container has been transferred to the next lower tray. As a container is loaded at the top of the tower, the shelf trays are operated to pass the container downwardly in zigzag fashion from one tray on one tower section to another tray on the other tower section until the container reaches the highest unloaded tray. This mechanized carton picker provides a means for efficient use of available space for storage purposes and a means for selective delivery of goods stored in the unit and is therefore well suited for use in the automated order picking system of the present invention.
A gantry robot, together with a mechanized carton picker tower and discharge output comprises a cell, forming a principal component of the present automated order picking system.